Those who need concealment 80 hours a week, year in and year out, find the Ankle Glove so comfortable to wear that they forget it's there....until they need it. The Ankle Glove's wide neoprene ankle band and velcro closure offer extended wearing comfort and unmatched security. Additional comfort is provided by sheepskin padding between the holster and ankle. It also features a reinforced thumb break for speed of draw and detailed molding for firearm retention. This right-hand model has a black finish and is compatible with your 2.125" barrel S&W J frame 640 Centennial. Calf Strap Sold Seperate.